Nondestructive transfer of complex molecular systems of various origins into aerosol phase by means of submillimeter irradiation of free-electron laser (FEL) of the Siberian center for photochemical research

A Novel Method of Probing the Fractional Composition of Nanosystems

“…In this situation, only the particles of the initial substance can enter the aerosol phase. A low quantum energy of the radiation does not allow one to split the material below the threshold of chemical bonds, which was confirmed previously in the experiments with such «delicate» biological structures as enzymes and DNA 4,5) . It should be stressed additionally thae investigation of the samples by means of TEM/SEM/DLS involves time-and labor-consuming cycles of sample preparation, measurement and analysis of the results obtained, while a single determination of the fraction Fig.…”

“…One can see that the problem connected wite determination of the particle size distribution and concentration with the help of DSA is reduced to measuring N(n) followed by solving the integral equation 4) . So, measurement of the particle size distribution of the aerosol with the help of the diffusion battery involves consecutive counting of the concentration of aerosol particles as the aerosol flow passes through the cascades of screens (the number of cascades is 8 in our case); counting is performed with the help of the condensation counter of aerosol particles.…”

“…The radiation of this laser is pulsed wite a pulse duration of about 50 picoseconds ane a pulse period of 180 nanoseconds; the laser wavelength is tunable within the range 120 to 240 micrometers with the relative radiation line width about 10 -3 , average power up to 400 W, and peak power up to 0.8 MW 3) . After the soft nondestructive ablation of biological macromolecules was discovered 4,5) , the possibility arose to develop a principally new method to measure the size of nanoparticles and nanosystems of all kinds. The phenomenon of soft nondestructive ablation involves the transport of macromolecules from a solid substrate or from solution into the aerosol phase under the action of laser radiatiof in the terahertz range; the structure and initial properties of the macromolecules aredretained.…”

“…In this process, an individual fraction of macromolecules forms an individual fraction of the aerosol particles. Binary and ternary mixtures form two or three fractions of the aerosol particles, respectively 4,5) . The molecular masses of these fractions correspond to the molecular masses of the initial components.…”

Poly(vinyl amine)–Silica Composite Nanoparticles: Models of the Silicic Acid Cytoplasmic Pool and as a Silica Precursor for Composite Materials Formation

“…16 In this study we have prepared PVA samples of various degree of polymerization (DP, 238À11000 units) and studied their influence on the condensation of silicic acid using a combination of light scattering (dynamic and static) methods (DLS and SLS), laser ablation using a free electron laser (FEL) in the terahertz region combined with aerosol spectrometry, FTIR spectroscopy, and electron microscopy. The application of laser ablation using a free electron laser is a novel application in this area of research but it has recently been shown 19 that under the action of submillimeter (120À240 μm) radiation from FEL, nanoparticles can be gently transferred from solution or solid phases to the aerosol state and their size and quantity measured with modern aerosol equipment. The advantage of ablation with FEL consists in correspondence between laser frequencies (40À80 cm À1 ) and vibrations of hydrogen bonds, and so destruction of covalent bonds is unlikely.…”